Hitherto, as this type of position holding device, a position holding device disclosed in Patent Literature 1 is known. The position holding device disclosed in Patent Literature 1 includes a base member, a rotating lever, a first stopper member, a second stopper member, and a torsion spring. The rotating lever is rotatably supported by the base member. The first stopper member abuts against the rotating lever when the rotating lever rotates in one direction, to thereby hold the rotating lever at a first position. The second stopper member abuts against the rotating lever when the rotating lever rotates in another direction, to thereby hold the rotating lever at a second position. The torsion spring is interposed between the rotating lever and the base member, and is configured to urge the rotating lever toward the first stopper member when the rotating lever is located at the first position, and to urge the rotating lever toward the second stopper member when the rotating lever is located at the second position.
The torsion spring used in the position holding device disclosed in Patent Literature 1 includes a coiled part mounted so as to be rotatable about a boss portion formed upright on the base member, and a first arm part and a second arm part formed so as to extend from both end portions of a wire forming the coiled part in a radial direction substantially orthogonal to an axial direction of the boss portion, and to face each other while sandwiching an engagement portion formed on the rotating lever from both sides thereof.